With the promise of free eclipse viewing glasses at businesses and venues across the country, most people think they have their eye safety covered, but professionals say there's more to keep in mind.

To ensure people view the eclipse safely Patrick Fitch M.D. of Clarksville Ophthalmology and Dr. Ming Wang of Wang Vision 3D Cataract and LASIK Center have answered a few eye safety questions from people on Facebook. Here are seven tips to make sure you don't go blind viewing the solar eclipse.

Exactly what are eclipse glasses?

Eclipse glasses are made specifically for looking up at the sun. Many are made of mylar, which reduces the power of ultraviolet, visible, and infrared energy generated by the sun, according to NASA. They are also used in welders masks.

But people should not look at the sun for prolonged periods of time even with certified eclipse glasses. Instead, they should look at the sun for a few seconds at a time, rest for a while and then look again, Wang said.

Can I use my sunglasses?

No, only eclipse viewing glasses will protect your eyes. "Regular sunglasses are designed for you to look indirect sun rays reflected from surfaces such as the road while you are driving," Wang said. "They are not designed, for you to safely look directly at the sun."

How do I know if the eclipse glasses I bought are safe?

Certified eclipse viewing glasses are ISO certified and marked 12312-2, for direct sun viewing, Wang and Fitch said. "There's a lot of cheap counterfeit solar glasses, and their not really certified," Fitch said, so double check. Wang said use glasses that are under three years old, without scratches or damage.

What about if I'm looking through my camera lens?

It's not safe to look at the eclipse through cameras, binoculars or telescopes without specialized solar filters, Fitch said. But make sure any filters are placed in front of the lens. Even eclipse glasses will melt behind binoculars or telescopes without a filter from the focused sunlight, Fitch said. "Looking through these devices with naked eyes is in fact more dangerous than the naked eyes themselves," Wang said.

Is it safe to remove my glasses when the sun is completely covered?

Yes. The eclipse will last for a couple of hours, but there'll be around 2.5 minutes or less in the path of totality, where the moon will completely block the sun. During that period of totality it is safe to look at the eclipse directly, but at all other times during the eclipse, you must keep your glasses on, Fitch said.

What if I recently had laser or other eye surgery? Will eclipse glasses still work for me?

Wang said that laser or cataract surgery with UV-protecting lenses is not enough to protect against damage. One must use eclipse safe glasses, which should protect your eyes as long as you're wearing them at all stages, except totality, which does not need glasses, Fitch said.

Is is safe to use a welding helmet?

Yes, welding helmets are safe to use if you have one, Fitch said. According to NASA, it must be number 14 welder's glass to be safe to use, otherwise it may not protect your eyes.

For more on eye safety and ways to protect your eyes during the solar eclipse, visit NASA.com or eyemdclarksville.com. Dr. Wang will host a public solar eclipse educational seminar at Wang Vision at 6:30 p.m. on August 17. To register visit wangcataractLASIK.com, or call 615-321-8881.